a-game

commit b687b427c267ffbfbc2c9a614c5a6c823b9aa0a9
parent 728a0a52d0964c1cc74c39466ad2828db6e82b5d
Author: amin <dev@aminmesbah.com>
Date:   Mon,  1 Jul 2019 23:05:58 +0000

Get keyboard input via the browser

FossilOrigin-Name: 9a06e01254efa2325c33260368021123adbd136eb6c2327810faa1ebadb95d08
Diffstat:
M
build_wasm.sh
 | 
1
+
M
src/platform_wasm.c
 | 
59
++++++++++++++++++++++++++++++++++++++++++++++++++++-------
M
src/platform_wasm_loader.js
 | 
20
++++++++++++++++++++

3 files changed, 73 insertions(+), 7 deletions(-)
diff --git a/build_wasm.sh b/build_wasm.sh
@@ -36,6 +36,7 @@ wasm-ld \
     --export=init \
     --export=render \
     --export=window_resize \
+    --export=key_callback \
     --import-memory
 
 rm $wasm_dir/*.o
diff --git a/src/platform_wasm.c b/src/platform_wasm.c
@@ -4,14 +4,35 @@
 
 extern unsigned char __heap_base;
 
-struct GameMemory game_memory = {0};
-struct GameInput game_input = {0};
-i32 g_width = PLATFORM_SCR_WIDTH;
-i32 g_height = PLATFORM_SCR_HEIGHT;
+// There's no standardized, nondeprecated way to get a numeric ID of a keyboard
+// key, so I guess we have to do that ourselves.
+enum WasmKey {
+    WASM_KEY_LEFT,
+    WASM_KEY_RIGHT,
+    WASM_KEY_UP,
+    WASM_KEY_DOWN,
+    WASM_KEY_S,
+    WASM_KEY_F11,
+};
+
+// TODO: map this in a nicer way
+global_variable int platform_input_map[NUM_GAME_BUTTONS] = {
+    [BTN_LEFT] = WASM_KEY_LEFT,
+    [BTN_RIGHT] = WASM_KEY_RIGHT,
+    [BTN_UP] = WASM_KEY_UP,
+    [BTN_DOWN] = WASM_KEY_DOWN,
+    [BTN_JUMP] = WASM_KEY_S,
+    [BTN_DEBUG_FLOAT] = WASM_KEY_F11,
+};
+
+global_variable struct GameMemory game_memory = {0};
+global_variable struct GameInput game_input = {0};
+global_variable i32 g_width = PLATFORM_SCR_WIDTH;
+global_variable i32 g_height = PLATFORM_SCR_HEIGHT;
 // TODO: replace with allocator
-char g_mem_buffer[1000] = {0};
-i32 g_mem_buffer_i = 0;
-u32 time = 0;
+global_variable char g_mem_buffer[1000] = {0};
+global_variable i32 g_mem_buffer_i = 0;
+global_variable u32 time = 0;
 
 i32 str_length(const char *str)
 {
@@ -64,6 +85,30 @@ void window_resize(int w, int h)
     glViewport(0, 0, g_width, g_height);
 }
 
+void key_callback(enum WasmKey key, bool key_action_is_pressed)
+{
+    enum GameButton game_button = NULL_GAME_BUTTON;
+    // TODO: Determine the button in a nicer way
+    for (enum GameButton b = 0; b < NUM_GAME_BUTTONS; b++)
+    {
+        if (platform_input_map[b] == key)
+        {
+            game_button = b;
+        }
+    }
+    if (game_button != NULL_GAME_BUTTON)
+    {
+        if (key_action_is_pressed)
+        {
+            game_input.button_states |= (1 << game_button);
+        }
+        else
+        {
+            game_input.button_states &= ~(1 << game_button);
+        }
+    }
+}
+
 PLATFORM_MEMORY_FREE(wasm_memory_free)
 {
     // do nothing
diff --git a/src/platform_wasm_loader.js b/src/platform_wasm_loader.js
@@ -6,6 +6,18 @@ let files = [];
 let gl = null;
 let gl_id_freelist = [];
 let gl_id_map = [null];
+// NOTE(amin): These values _must_ match the corresponding ones used by the
+// platform layer in `enum WasmKey`.
+// By the way: Thanks a lot, W3C, for not having any standardized _numeric_
+// representation of a key.
+const key_numeric_codes = {
+    ArrowLeft: 0,
+    ArrowRight: 1,
+    ArrowUp: 2,
+    ArrowDown: 3,
+    KeyS: 4,
+    F11: 5,
+};
 imports["webglAttachShader"] = function(program_id, shader_id) {
     let program = gl_id_map[program_id];
     let shader = gl_id_map[shader_id];
@@ -215,6 +227,12 @@ function file_load(name) {
     });
     return promise;
 }
+function on_key_event(e, key_is_down) {
+    let sane_numeric_code = key_numeric_codes[e.code];
+    if (sane_numeric_code !== undefined) {
+        exports['key_callback'](sane_numeric_code, key_is_down);
+    }
+}
 window.onload = async function() {
     let ctxopts = {
         alpha: false,
@@ -241,6 +259,8 @@ window.onload = async function() {
     exports = instance['exports'];
     canvas_resize();
     window.addEventListener("resize", canvas_resize);
+    window.addEventListener("keyup", (event) => {on_key_event(event, false)}, false);
+    window.addEventListener("keydown", (event) => {on_key_event(event, true)}, false);
     if(!exports['init']()) {
         error_fatal("Game initialization failed.");
     }